This application contains subject matter which is set forth in the U.S. Patent Disclosure Document Number 499878, dated Sep. 13, 2001.
The invention relates to power transmission flow conductor fittings and particularly to flared tubing connections without the use of threaded connections. The sealing integrity of the line connection is a major consideration.
Most tube and hose connections feature engagement for fastening flared transmission lines and depend upon the mechanical clamping force applied to frusto-conical engaged surfaces of the fitting for sealing.
Most of the current threadless transmissions line connections feature elastomeric sealing elements which depend upon compression to initiate and maintain the fluid seals. The frusto-conical shaped engagement joint common to the flared fittings is not utilized.
These threadless connectors are usually limited to relatively low pressure (less than about 500 psi) fluid transmission applications because of their limited sealing integrity. Such threadless connectors are typically utilized in some automotive fluid systems and in some domestic plumbing installations.
There are many advantages of a threadless tube fittings for connecting fluid transmission lines:
A. Reduced manufacturing and installation costs
B. Simplified installation
C. Applicable in inaccessible installation (limited space for using a wrench)
D. Elimination of possible leakage source, damaged threads, and
E. Rapid installation and disassembly.
The present invention provides an internal mechanism in the engaged flared connection of a transmission line to maintain a sealed joint without a torqued-threaded fastener.
The internal mechanism comprises a hollowed piston featuring a frusto-conical shaped surface for engaging and sealing the flared end of a transmission line. Said piston contains a radial sealing means to seal its radial clearance with the bore and to isolate the end which is axially spring biased and exposed to the pressure of the transmitted fluid. The resulting hydrostatic pressure axial force on the piston supplements the compressed mechanical spring force applied at the assembly of the fitting connection. The combination of the mechanical spring force and the hydrostatic pressure force assures sealing contact of the engaged frusto-conical shaped surface with the flared end of the tubing.
The applied hydrostatic force is proportional to the pressure of the transmitted flow in the transmission line.
A mechanical spring is internally compressed between the hollowed piston and a shoulder within the bored body to prevent the piston frusto-conical shaped end from losing seal contact with the flared end of the tubing during low pressure flows.
At assembly of the line connection an axial force is applied against the flared tubing to displace the hollowed piston and to compress the spring means so as to insert a retention ring into the circular groove located in the bore. Part of the retention ring axially supports the enlarged flared end of the tubing to prevent it from being disengaged by the force of the compressed spring means and by the hydrostatic pressure force.
The engaged frusto-conical shaped end of the piston and the flared end of the tubing are preloaded by the compressed spring at assembly of the fitting. As the pressure of the transmitted flow increases, the resulting hydrostatic pressure force increases on the joint to ensure contact and prevent separation.
Unlike the prior art of the threadless fitting connectors relying exclusively on an xe2x80x9cOxe2x80x9d ring to simultaneously seal two (2) annular clearances to prevent external leakage, the threadless flared fitting connector hereof provides a more dependable xe2x80x9cOxe2x80x9d ring seal of one annular clearance and a surface-to-surface sealing frusto-conical contact which is axially spring preloaded at assembly and axially loaded further by a hydrostatic force correlated to the pressure of the transmitted fluid.
Because of the superior sealing feature in the present invention fitting connector it is anticipated that its fluid pressure capability should be at least 50 percent greater than the current state-of-the-art threadless fitting connectors.